Background: In 2010 the VA began implementing Patient Aligned Care Teams (PACT), a nationwide patient- centered medical home (PCMH) model, designed to transform primary care into team-based care in over 900 primary care clinics. PACT is focused on improving access to care and coordination between primary and specialty care through the use of interdisciplinary teams composed of primary care providers, RN case managers, clinical and administrative staff, and patients. Specific Aims: Aim 1 will investigate whether PACT is implemented differently by facilities in relation to the percent of minority Veterans served at a facility. Aim 2 will investigate whether the effects of PACT on healthcare utilization differ by racial/ethnic minority group. Methods: For Aim 1, clinics will be categorized as low (<5%), medium (5%-15%), and high (>15%) based on the percent of minority patients comprising their patient population. We will test whether facilities serving higher proportions of minority Veterans have lower PACT implementation domain scores adjusting for other covariates using multivariate linear regression. For Aim 2, using an age stratified (above and below 65) interrupted time series design this study will evaluate whether compared to white veterans, individuals of racial/ethnic minority groups have differential quarterly utilization (outpatient visits, specialty care, mental health, and ambulatory care sensitive conditions) associated with PACT after adjusting for potential confounders. It will be estimated using mixed effects negative binomial models with random intercepts for patient and clinic for 2003-2012. Impact: The proposed research will make a unique and critical contribution to AHRQ's research portfolio in quality and effectiveness with a significant focus on the priority population of racial/ethnic minority adults. This study will determine whether implementation challenges exist of particular PCMH domains (they have lower domain scores). If the proposed research demonstrates facilities serving high proportions of minority Veterans have lower scores in PACT implementation, the particular facilities can be targeted for intervention (Aim 1). Future research could evaluate whether trends in PCMH implementation differ by the percentage of minority Veterans served. In addition, this study is the first to characterize trends in healthcare utilization for minority Veterans and to test whether minority Veterans' healthcare utilization is differentially affected by a patient- centered medical home model of primary care (Aim 2). If differences in effects on utilization are found, future research could evaluate whether they are maintained, closed, or widened.